WPA Key encrypted WiFi network is not as safe as you think anymore, with ariodump (airodump) and winaircrack and a bit of luck you could hack WPA key encrypted network and acquire the WPA key.
How to hack a WPA key encrypted WiFi network
First, please check if your WNIC driver is supported by ariodump otherwise you have to download relevant driver or use another WNIC for your laptop. Second, download winaircrackpack.zip and run ariodump, choose the number of your WNIC adapter for the network interface index number. Then select your network interface type and it only support two types. You also have to select the channel from 0 to 14, if you choose 0, it will monitor all channels. Then enter the file name and choose no for only write WEP IVs. Now hit enter and it starts to capture data. Then, you need some luck; pray that some clients are logging on to WLAN while you capture data, because you need the data including the whole logging process-request/challenge/acceptance.
So this process may take a long time to finish, but if you are lucky enough it may only take a few minutes. Thirdly, run winaircrack and click general, choose WPA-TSK for the encryption type, and select your .cap file resulted from ariodump. Then click WPA in the left and enter the path and name of your dictionary file. You could make the dictionary yourself or download one at lastbit.com/dict.asp. Now you are all set and click Aircrack the key, a CMD window prompts and you have to choose the BSSID you want to crack and hit enter.
You also need a bit of luck
If it shows you have got 1 handshake, then you are a lucky guy, otherwise if it shows 0 then you have to capture data again. If the correct WPA key is included in your dictionary file then you will get the key in a few minutes, otherwise you have to make another dictionary file.
So the key of the crack consists in two things, if you have captured the data of the whole logging process, and if the correct key is included in your dictionary file, hence you need a bit of luck. If you meet the above mentioned two requirements, you will get the WPA KEY!